Disastrous Automotive Soldering Connections

A few weeks ago, my neighbor came to me with a problem with his 1995 GMC Sierra half-ton truck. The daytime running lights worked fine, but he had no headlights at night. We checked the Internet for suggestions.

He had also called a few mechanic friends to get their opinion, and each of them agreed that the turn signal/high beam switch on the steering column was faulty.

After several hours of struggling to get the switch out, and grumbling about the poor job that was done installing an aftermarket remote start system, we determined that we could not open the switch assembly to perform a repair. Lacking enough information to actually test the switch properly, we decided that a replacement was in order. We eventually found one for under $100 from an online source and ordered it.

The switch arrived a few days later and we installed it, only to find that the problem still existed. We pulled out the Haynes Repair Manual, went through the electrical drawings for the electrical system, and started to trace the power supply from the battery to the switch.

Most of the wire colors, but not all, were correct in the manual, which caused a few problems. Eventually, we discovered that the power stopped at the dashboard headlight power switch. This was easily pulled and we took it to the bench for a closer look.

Using an ohm meter, we found that buried in the guts of the switch was a thermal breaker that was open. There was no reset button for this. I cut the breaker out and opened it up to find that the contacts were very pitted, and the bimetal spring had no spring left in it. In order to save another $100, I replaced the breaker with an externally mounted fuse, reinstalled the switch, and everything worked once again.

I am still trying to figure out why GM would install a thermal breaker inside the dashboard switch when there are spare fuse positions in both of the fuse panels in this truck.

At the same time, we also repaired the daytime running light modules in my 2003 Honda CRV, his 1995 Honda Accord, and his wife’s 1999 Honda Accord. Amazingly, all three vehicles had the same problem: The daytime running lights were intermittent.

We pulled the module out of the CRV first, and fortunately, the module was not potted, so we were able to open it. The problem was immediately apparent: several cold solder joints on one of the relays. I re-soldered every joint on the board because there was so little solder used in manufacturing that future failures were inevitable. Sure enough, the problem was solved.

We then pulled the module on his Accord and found exactly the same problem -- exactly the same pins, even! The same remedy with the same result, the problem was resolved.

Finally, we pulled the module from his wife’s Accord, and discovered that while her lights were working most of the time, the exact same solder connections were cracked, soon to be a problem. Same remedy, with the same result.

We figured that by spending an hour doing all three vehicles, we probably saved $1,500, and got a better solution than by simply replacing the module. We also found that the wiring and quality of the Hondas was much better than the GMC, and the ease of access was much better, as well.

This entry was submitted by Clint Millett and edited by Rob Spiegel.

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We think it's the control module.....even though I took it to the shop and tested the crap out of it and was fine we still think it's bad..I just have to buy one and find out. Just sucks once you install it you own it.

"I am still trying to figure out why GM would install a thermal breaker inside the dashboard switch when there are spare fuse positions in both of the fuse panels in this truck."

One guess is that GM considers headlights very important. A circuit breaker will reset itself to keep you going. Circuit breakers take more room than fuses. Perhaps there wasn't the room for a breaker. Yea right.

Then of course there's the cynical reason of "New Improved" which usually translates to mean, "New Improved Profits". Replacing a switch makes the dealer and GM more money than simply replacing a fuse or circuit breaker.

If the switch is usally the problem, then it's an OK design as it is often costly and frustrating to trace why a fuse has blown or a breaker opened.

Another posibility is that the thermal breaker is right in the switch in case the switch overheats and would otherwise risk starting a fire.

The reason for using an automatic reset breaker in the headlight circuit is that the headlights are important! If they were fused and a random fuse failure occurred a person could be in a lot of trouble. Momentary short circuits and overloads do happen in cars, and the breaker is supposed to reset and restiore lighting. Unfortunately purchasing gets into the picture and quality is reduced until the price target is met. One of my cars did wind up with a military surplus breaker for the lights. It cost me $2, and while it did trip once or twice it was always able to be easily reset.

My impression is that many soldered parts in cars are quite poorly soldered, and that the lead free solder is even worse. So perhaps the liability should be placed on those idiots in europe who came up with such a stupid idea.

There was only one vehicle where the breaker did trip and automatically reset, on my 1968 Javelin (AMC). I was driving from Toledo to St. Louis in the middle of the night and the headlamps suddenly shutoff, and they came back on about a minute later. Fortunately it was a full moon and we could safely get to the side of I-70 to stop. It happened twice and then never again.

Most likely the thermo-breaker got a little hot due to the number of hours we had been driving continuously (no excuse, we should be able to drive 24 hours without this happening). We never drove that long at a stretch again and the problem never reoccurred.

"Someone mentioned that this was a "cost saving" move on GM's part. You bet it was. It saved them all of $2 if that. However, the cost for the replacement turn signal/high beam switch mechanizm is over $600 in Canada from GM and the dash light switch is over $400. I would rather have paid the extra $2 at the time of manufacture than to get hit with the tab for new switches."

I worked for 10 years preparing electrical system information for GM service manuals. I clearly remember the time some brillient person removed the rear door courtesy lights, the front footwell courtesy lights, and the glove box light. The reduction in wires and connectors would save several dollars on each vehicle and they made nearly a half million of that vehicle class yearly. That is several million dollars per year and I am sure he was honored with a bonus and something to hang on his cube wall.

This was for the C/K utilities which included the Cadillac Escalade Platinum Edition which went for about $80,000. And they wokdered why people looking for a vehicle in that cladd didn't even stop at a Cadillac dealer, but went stright to Mercedes, BMW, Lexus, Range Rover, etc. They even had a TV commercial ridiculing them. Even my Volvo station wagon selling for half that price has a glove box light and front footwell courtesy lights. And today, GM seems only a shadow of its old self.

Also, they are in the business of selling service and replacement parts.

Regarding lead-free solder. It would appear that after several years the world has come up with an acceptable lead-free solder and developed processes that provide reliable (more or less) solder joints. I have every confidence the EU or someone will discover a new gremlin that will need to be outlawed. Perhaps tantalum or copper, or something like G10 epoxy or RIM plastic. When the politicians apply political solutions to engineering problems the outcome is predictable; the engineering world will complain loudly while quietly coming up with a solution. It's usually easier to deal with difficult physics and chemistry problems than misinformed politicians. Regarding resettable circuit breakers. These have been mounted on the headlight switches seemingly forever. When these breakers cycle, they pit; they are not designed for repeated cycles and if a trailer or running lights are incorrectly wired into a lighting circuit (as would happen on a pick-up for instance), the breaker may cycle with the turn-signals (I've seen this!). Ultimately the breaker will cease to function due to high contact resistance. The purpose of the breaker is to protect downstream wiring without disabling the remainder of the lighting functions (parking lights, dash lights, etc.).

The Honda modules were all exactly the same and were used from at least 1995 to 2003 as these are the years of the three cars involved. They use through hole components, a single sided PCB and I would be surprised if the total cost of the parts involved amounted to more than $5.00, not that this matters. They also were not coated with a conformal coating of any sort, although corrosion was not an issue with any of the three. Again, the problem was exactly the same on all three modules, the relay pin connections had cracked. None of them had enough solder on them.

The problem is the QUALITY of the manufacture of these devices. I managed on my vehicle to get 200K Km's before the Day-Time driving lights became intermittant (2003 CRV). There was no scorching of the solder connections. The solder was THIN and had cracked. The other vehicles were a 1995 and a 1998 Accord with less than 100K Km's.

I have been in the electronics industry for over 40 years and have seen some well made products, some well designed products, and many well designed, but poorly manufactured products. This Honda module was/is poorly manufactured in my opinion.

The GMC manual (yes, we did have one) suggested to replace the headlight high beam, turn signal switch assembly, as did the shops around town, to repair the problem my neighbour had. When this did not work, he asked me to help investigate the problem. The problem was the thermal, resetable breaker in the dash mounted, headlight switch.

Someone mentioned that this was a "cost saving" move on GM's part. You bet it was. It saved them all of $2 if that. However, the cost for the replacement turn signal/high beam switch mechanizm is over $600 in Canada from GM and the dash light switch is over $400. I would rather have paid the extra $2 at the time of manufacture than to get hit with the tab for new switches. There was a reason that my friend could not find either switch at the scrap yard, even after looking at 50 or so vehicles. Many people had the same problem.

I appreciate that they used the thermal breaker for the reason that was mentioned by several people. I take issue that the breaker was hidden within the dash mounted switch and NOT placed at the fuse block where it belongs. If safety was really their concern, then it would have been acessable so that when it failed at night time, someone would be able to repair the problem and get to their destination.

Interestingly, I have been driving for 40 years, and have never seen my headlights coming on and off as a thermal breaker trips and resets? Have any of you? I have driven Mercedes, Honda, GMC, Ford, Chrysler, Volkswagon, Toyota, Datsun, Austin Healey, Austin Mini's, Beaver Motor Homes, Empress Motor Homes, and a school bus, but haven't seen a thermal, resettable breaker hidden inside a switch in any of them other than this truck. They all had accessable over current protection devices. Yes, even for the headlights. I am sure there are other models and other manufacturers that incorporate similar methods into their devices but I haven't come across them.

Critic wrote "As for the Honda running light modules: process design by monkeys. "...wiring and quality of the Hondas was much better than the GMC?" You provided several examples of electrical problems with Hondas, so I am not convinced this is true. Do you have statistics to back up this statement?"

It's got to be true. Even Yugos have better electrical design than General Motors. General Motors' favorite trick is to run more than rated current through their connectors. Example: the A/C-heater blower draws at least 10 amps. The current is switched by a relay with tiny pins which plugs into a Packard connector with tiny receptacles surely not rated for this much current. When it starts to fail, it overheats and melts the plastic base of the relay. This causes the support for the spring-loaded armature to draw away from the Normally-Open contact and the relay ceases to make contact. It's pretty easy to fix the relay--pry off the cap and bend the armature support, possibly while heating the base with a heat gun. After two or three events you notice that the socket contact is mostly burned away.

It fails so commonly that when you go to the parts counter and ask for the heater connector, the parts counterman has it in stock and gets it without looking it up. The GM factory shop manual devotes several pages finding and replacing each of the various connectors used on the car. And the parts counter has the individual contacts for each of the connector sockets, as well as new sockets with pigtail leads.

There was a recall on the wiper board on the 1995 GM and Chev trucks for exactly that reason. You could have gotten the board (and installation) free. Unfortunately the same board was installed in my 1995 Chev APV minivan and those were not eligible for the free replacement.

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